Bolster spring unit



Patented May 18, 1937 UNITED STATES Donald F. Sproul, Chicago, Ill.. assignor Vto 'Card'-L well-Westinghouse Company, a corporation "of Delaware Application January 15, 1934, Serial No. 706,580

6 Claims.

.sisting both the compression and expansion of the unit.

A further object of the invention is the provision of a new and improved bolster spring unit having a novel friction sleeve element comprising aplurality of segments integrally connected together. y

A still further object of the invention is Vthe provision of a new and improved bolster spring unit so constructed as to eliminate the formation `.of objectionable. shoulders on the friction surfaces during the normal use of the device.

Another object ofthe invention .fis the provision of new and improved bolster spring units that are'inexpensive to manufacture, easily assembled, eicient in operation, strong and'rugged in construction and that may be readily substituted for Ythe conventional bolster supporting spiral springs in railway cars and the like.

Other and further objects and advantages of the invention will appear from the following description, .taken in connection with the` accompanying drawing, in which:

Fig. 1 is a vertical section of the springv unit;

Fig. 2 is a section on the line 2-2 of Fig. 1; and

Fig. 3 is a perspective view of the base member.

It is common practice to support the bolster of railway trucks by a plurality of spiral springs at each end' of the bolster. 'I'hese springs while cushioning. the downward movement of the car are free to give impetus to its upward' movement on the rebound of the springs, thereby prolonging the period in which the car continues to vibrate or oscillate.

`vibration of the car, there is vreadily built up a f vibration that may becomeextremely hazardous in that it may be the cause of serious accidents. The present invention seeks to remedy these difiiculties by the provision ofa spring unit that may be substituted for one or more of the `conventional spiral bolster springs.

Referring now to the drawing in which is disclosed one embodiment of the invention, for `the purposesof illustration, thereference character It designates a spring unit comprising a supporting member I I having the flange I2 `andthe inner friction member or friction post I3 extend- 5 ing downwardly therefrom. Thepost I3 is preferably, though not necessarily, hollow and has a partition I4 therein. The partition I4 has an axial opening I5 .therethrough for the reception of a retaining bolt I6, ask will presently appear. 10

In .the form of .construction selected to illus-f trateone embodiment of the invention, the ange I2 and friction post` I3 are circular in cross section. The diameter of the circular flange I2 is substantially the same vas that of the external .115.

diameter of the conventional-bolster spring and the height of the unit is the same as saidsprings, whereby these units may be substituted for said springs in railway trucks.

Suitable means are provided for frictionally resisting ,the compression ofthe unit. In the form of `'construction shown, this means comprises an` outerffriction member or friction sleeve I'I extending about the friction post I3 and adapted to be forced into frictional contact therewith. .25 This sleeve hasfa slot I8 extending longitudinally thereof. The slot I8 permits the sleeve to bel forced radially inwardly into frictional contact with the friction post. Y

The sleeve I'I is preferably, though not .neces- 30 sarily, cast and, in order to insure the desired flexibility in .compressing the same, its inner surface may be provided with a pluralityof grooves I9extending longitudinally of the sleeve, forming a `plur-ality of friction surfaces or segments 3 20. These grooves insure uniformity in the flexing of the walls of the sleeve with a consequent uniformity of 'frictional contact of the sleeve with all. parts of the friction post when the unit is sleeve I'I may be considered as consisting of .a plurality of segments 2'connected together temporarily for convenience in casting and assembling. Thelower and vupper ends of the sleeve.50 are beveled, as at 2l and 22, respectively, to formwedging surfaces.

A spring seat member. 23 isprovided for co- .n operating with the upper beveled `ends of the sleeve I'I` for clamping the same against .ther-5:5

post I3. The spring seat 23 has an upstanding hollow portion 24 and a flange 25 at its lower end. The upstanding portion 24 is cylindrical in the construction shown, and has its upper end provided with an annular inclined or wedging surface 26 which engages the beveled surface 22 to force the upper end of the sleeve I'I into frictional engagement with the post I3 when the unit is compressed. A spring 28 is interposed between the anges 25 and I2 and tends to hold them apart.

Suitable means are provided for compressing the lower end of the friction sleeve I1 when the unit is compressed. A base or thrust member 29 having an upstanding cylindrical projection 3l, extending through an axial opening in the spring seat member 23, is employed for this purpose. The upper end of the projection 3| is provided with an internal annular beveled or Wedging surface 32 that engages the beveled or wedging surface 2| of the friction sleeve I'I for compressing the lower end portion of said sleeve.

The base or thrust member 29 is provided with a flange 34 which is preferably circular and of substantially the same diameter as the flange I2. The truck bolster is seated on the flange I2. Y

Appropriate means are provided for holding the parts in assembled relation during shipment and for limiting the expansion of the spring unit. In the construction shown, the bolt I6 is employed for this purpose.

The base 29 is provided with an inwardly depressed portion 35V forming an angular socket 30 having an axial opening 36 therethrough in line with the opening I5 in the partition I4. A bolt having its head seated inthe socket extends through the aligned openings and a nut on its opposite ends holds the parts in assembled relation. The nut may be adjusted to vary the height of the unit and in practice is adjusted to 'place the spring under more or less initial compression.

In the operation of the device, a shock on the bolster forcing the same downward will tend to force the thrust member 29 upwardly causing a wedging action of the surfaces 2l and 32 to compress the lower end of the sleeve II and simultaneously forcing said sleeve upwardly along the post, bringing its beveled upper edge 22 into wedging engagement with the Wedging surface 26 of the upstanding hollowT portion 24 of the spring seat 23, thereby forcing the upper end of said sleeve into frictional engagement with the friction post I3. The upward movement of the spring seat is resisted by the spring 28. Further compression of the unit is resisted by the frictional resistance set up between the post and sleeve and by the spring 28. On release, the spring 28 expands and tends to loosen the wedging faces. The parts are so constructed that the unit while it expands sufficiently rapid to follow the bolster, movement is retarded by frictional resistance to such an extent as not to add material impetus to the upward movement of the bolster, and, hence, will dampen each downward 'movementof the car without rebounding to materially accentuate its upward movement.

In the normal operation of the device, the sleeve Il will move but a small distance along the post I3, and, consequently, were the post of uniform diameter throughout its length, the continual wear on a limited portion only of the post would in time reduce the same and form a shoulder above this reduced portion that would interfere with the relative movement of the sleeve and post during abnormal shocks. In order to avoid this diiculty, the post is reduced, as at 31, beyond the portion of the post that is engaged by the sleeve during the normal operation of the device, thereby avoiding the formation of a shoulder on the post.

The capacity of the unitV may be varied to meet different conditions by varying the angles of the wedging faces of the elements within certain limits. Likewise, the lag in expansion of the unit may be varied by varying the angle of the Wedging faces.

In practice, one of the friction units is substituted for one of the springs at each end of the bolster. In order to balance the parts, the unit is preferably substituted for a forward spring on one end of the bolster and one for a rear spring on the other end.

Inuse, the unit may be changed end for end. Under certain conditions, this is desirable because of the shortness of the sleeve 3|, which will permit a more or less rocking movement for the accommodation of such movements in the bolster.

It is thought from the foregoing taken in connection with the accompanying drawing that the construction and operation of my device will be apparent to those skilled in the art and that changes in size, shape, proportion and details of construction'may be made without departing from the spirit and scope of the appended claims.

I claim as my invention:

1. In a bolster spring unit, a supporting member comprising a friction post and an integral ange extending about the same, a friction sleeve extending about said post and frictionally engaging the same, said sleeve having tapered ends forming Wedge faces, a base having a thrust member provided with a wedging face on its upper end engaging a wedging face on said sleeve, a spring seat member surrounding said sleeve and thrust member and having a wedging face engaging a wedging face on said sleeve, and a spring anchored on said sleeve and engaging `means engaging said tapered ends for forcing said friction means into frictional engagement with said post upon the compression of said unit and upon the expansion thereof, means for forcing said friction means into frictional engagev ment with said post upon the release of said unit and a single spring surrounding said post and all of said means for restoring the parts to normal position after compression.

3. In a spring unit, a friction post, an elongated sleeve frictionally engaging said post and movable longitudinally thereof, means for forcing said sleeve into frictional engagement with said post when said unit is compressed and when the same is expanded, and means including a single spring for resisting the compression of said unit, said post being reduced beyond the surface engaged by said sleeve during the normal operation of said unit, said spring surrounding said first named means and constituting the sole resilient means for resisting the compression of said unit.

4. In a spring unit, an inner friction member having a flange and a friction post, an integral segmental sleeve for frictionally engaging said post and sliding longitudinally thereof, said sleeve being split longitudinally thereof and having a plurality of grooves therein extending longitudinally of said sleeve and parallel to the axis thereof, means having Wedging faces engaging Wedging faces on said sleeve for compressing said sleeve radially inwardly during the compression of said unit and resilient means comprising one spring only for restoring the parts to normal position after release, the exterior oi' said resilient means constituting the exterior of the intermediate portion of said unit.

5. In a spring unit, an inner cylindrical friction member, a sleeve slidable on said member longitudinally thereof, said sleeve being split 1ongitudinally and having its edges spaced apart, said sleeve having a plurality of grooves on its inner surface extending longitudinally thereof in parallel relation, means for compressing said sleeve radially inwardly into frictional engagement with said member When said unit is compressed, and a single spring surrounding said sleeve, and means for causing said means to compress said sleeve both When said unit is compressed and when it is released.

6. In a spring unit, an inner friction element, an outer friction means engaging said element, said means having its ends tapered to form annular Wedging surfaces, a thrust member having a Wedge surface for engaging the Wedging surface at one end of said means, a spring seat member of a length greater than saidfriction means having a Wedging surface for engaging the wedging surface at the other end of said friction means, said spring seatmember surrounding said thrust member, a single spring surrounding said friction means and engaging the outer end portion of said spring seat member, tending to separate said element and seat for causing said friction means to frictionally engage said friction element both when said unit is compressed and when' it is'released.

DONALD F. SPROUL. 

